1. Field of the Invention
The present invention is directed to making lenses on a wafer level, in particular to using wafer processing techniques to create a desired lens functioning, illustratively starting with substantially identical base lenses formed on a wafer level, and structures formed thereby.
2. Description of Related Art
Previous wafer level manufacturing techniques have assumed that the lenses made on the wafer level were identical within required parameters for their end use. As tighter tolerances are required, this assumption may no longer be realistic. As the use of arrays of micro-optical lenses becomes more prevalent, differences between lenses therein may result in erroneous functioning. Further, many applications are now requiring the use of microlens arrays in which the microlenses therein have different properties, e.g., different focal lengths. Typically, such different arrays were created using different parameters for the underlying lenses themselves. However, it is easier to create a wafer of substantially identical microlenses than to try to adjust the parameters for individual microlenses thereon.
This creation of an array of different lenses is particularly difficult when the microlenses are to be refractive lenses created using reflow techniques. When etching reflowed lenses into a substrate, lenses having different radii of curvature require the chemistry used during etching to be altered at different points. Thus, the creation of an array of different reflowed refractive lenses on a wafer level becomes impractical.